| 摘要 |
Process for hydrotreatment, in at least two stages, of a heavy hydrocarbon fraction containing asphaltenes, sulphur-containing impurities and metal impurities, in which: a) in at least one first stage (26,27) known as hydrodemetallation, the hydrocarbon feedstock and hydrogen are passed over a hydrodemetallation catalyst, b) in at least one subsequent so-called hydrodesulphurising stage (28,29) the product from stage a) and hydrogen are passed over a hydrodesulphurising catalyst. The invention in which the hydrodemetallation stage consists of one or more zones, each containing a hydrodemetallation catalyst operating as a stationary bed is characterised in that this or these zone(s) are preceded by two protective zones arranged in parallel (24,25) each containing a stationary bed of a hydrodemetallation catalyst, these two protecting zones operating alternately. <IMAGE>
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